1. Field of Invention
The present invention relates to a speaker, and more particular to a speaker with a diaphragm arrangement which comprises a middle foaming layer being sandwiched between a first layer and a second layer for simplifying the structural configuration of the diaphragm arrangement and for substantially reducing the manufacturing process of the diaphragm arrangement to incorporate with the speaker.
2. Description of Related Arts
A conventional speaker generally comprises a speaker frame, a voice coil, and a diaphragm to reproduce the voice coil signal from the voice coil. The conventional diaphragm comprises a middle layer sandwiched between two covering layers, wherein the middle layer is made paper or aluminum with a beehive-shaped structure as shown in FIG. 1. The purpose of the diaphragm is to accurately transform the voice coil signal waveform from the voice coil to an audio sound. Inaccurate reproduction of the voice coil signal results in acoustical distortion. The main parameter of diaphragm is Fo value illustrating the amplitude of vibration of the diaphragm. The major characteristics of the diaphragm are light weight and high elasticity coefficient. The stiffness and damping of the diaphragm play a crucial role in accuracy of the reproduced voice coil signal. However, the conventional diaphragm has several drawbacks.
Due to the beehive-shaped middle layer, the surfaces of the middle layer are not two flat surfaces. Therefore, the manufacturing process of the diaphragm requires special equipment to attach the middle layer between the two covering layers. In addition, due to the uneven surfaces of the middle layer, the manufacturing process of the diaphragm is very complicated that the defect rate of the diaphragm is relatively high, especially when the diaphragm is made of aluminum.
In order to reduce the defect rate of the diaphragm during the manufacturing process, the middle layer can be made of synthetic fiber, such as aramid fiber. However, the cost of the synthetic fiber made middle layer is relatively high such that the manufacturing cost of the diaphragm will be substantially increased. Although the middle layer can be made by paper to reduce the cost of the diaphragm, the paper made middle layer is lack of rigidity to reduce the quality of the beehive-shaped structure of the middle layer for the diaphragm.
Since the beehive-shaped middle layer defines a plurality of chambers on each uneven surface, it is impossible to apply adhesive evenly on the uneven surfaces of the middle layer to attach the covering layers onto the uneven surfaces of the middle layer. In other words, the surface contacting areas between the uneven surface of the middle layer and the covering layer will be minimized by the beehive-structure of the middle layer. As a result, the covering layers cannot be securely glued on the uneven surfaces of the middle layer to form the diaphragm. Furthermore, when the adhesive is applied on the uneven surfaces of the middle layer, the adhesive will unavoidably fill into the chambers of the middle layer. Once the chambers are filled by the adhesive, the adhesive cannot be removed from the chambers. Therefore, the elasticity of the diaphragm will be substantially reduced by the adhesive being filled into the chambers. In other words, the conventional method for manufacturing the diaphragm has a low yield and requires special equipments and special adhesive.